A gardener planted trees in rows and columns such that the number of rows is seven more than the number of columns. If the total number of rows and columns is 87, find the number of trees.

Question: A gardener planted trees in rows and columns such that the number of rows is seven more than the number of columns. If the total number of rows and columns is 87, find the number of trees.

Solution:
Let the number of columns = x.
Then, number of rows = x + 7

According to the question,
x + (x + 7) = 87
⇒ 2x + 7 = 87
⇒ 2x = 80
⇒ x = 40

Number of rows = x + 7 = 40 + 7 = 47

Total number of trees = rows × columns
= 47 × 40 = 1880